The primary objective of the imaging and Radiation Oncology Core (IROC) Group is to provide scientific and technical expertise for incorporation of appropriate, integrated Quality Assurance (QA) and image data management for both imaging and radiotherapy (RT) in applicable trials conducted by the National Clinical Trials Network (NCTN) Program. The leading QA centers; RPC, QARC, RTOG QA, ITC, ACRIN and CALGB/SWOG Imaging Core lab, in the current NCI Cooperative Group Program have joined together to form the IROC Group, administratively organized through the American College of Radiology (ACR) Clinical Research Center. The creation of IROC capitalizes on existing infrastructure and expertise at QA Centers currently providing services to the NCI Cooperative Groups. Work flows, processes and information systems currently in place will be further enhanced taking the best practices and standards in an integrated vision. The interdependencies between imaging and RT will be synergized in this QA Group eliminating duplication of services and optimizing towards efficient and effective workflows. A major strength of IROC will be the development of consistent standard operating procedures for all imaging and RT aspects of the NCTN and to facilitate a seamless flow of imaging and RT patient case datasets across the network. IROC's organizational structure allows the delivery of a broad array of imaging and RT QA services including Site Qualification; Trial Design Support; Credentialing; Data Management (Pre- and Post- Review); and Case Review. An information technology infrastructure will be developed that harmonizes IROC services, data collection, assessment and management for the NCTN Groups' clinical trials. IROC will implement programs that assure consistent high quality imaging and RT planning/delivery across the NCTN participating sites. IROC members will collaborate with the NCTN disease/modality committees within each Network Group to provide an optimal and effective imaging and RT core service. IROC will analyze QA data obtained prospectively/retrospectively to further advance QA science. IROC will manage all aspects of QA for NCTN trials that includes imaging and/or RT with the shared goal to achieve the best possible trial outcomes.